Learning the passive voice help us focus on the action and the result, rather than on who performs the action. In many real-world situations. For example, in news, formal writing, academic reports, and instructions, the doer of the action is unknown, unimportant, or obvious. That’s where the passive becomes essential.
This lesson reviews the form and use of the passive in all main verb tenses included at B1 level.
1. Why We Use the Passive Voice
We use the passive when:
The doer is unknown: My wallet was stolen.
The doer is not important: These phones are made in Korea.
The result is more important than the person: The meeting has been cancelled.
The sentence sounds more formal or objective: The survey will be analysed next week.
Non-defining relative clauses help us add extra information about a person, place, or thing. This information is not essential to understand the sentence. The clause contains an additional, interesting detail.
👉 We always use commas with non-defining relative clauses. 👉 We NEVER use “that” in non-defining clauses.
What Is a Non-Defining Relative Clause?
A non-defining relative clause:
gives extra information
is separated with commas
uses relative pronouns like who, which, where, when, whose
can be removed and the sentence still makes sense
How to Form Non-Defining Relative Clauses
Non-defining relative clauses give extra information about a person, place, or thing. This information is not essential to understand the main idea. We always use commas to separate the extra information.
1. Structure
Main clause, relative pronoun + extra information, rest of the sentence.
2. Common Relative Pronouns (for Non-Defining Clauses)
Relative Pronoun
Used For
Example
who
people
My English teacher, who is from Canada, is very friendly.
which
things / animals
The book, which I finished yesterday, was fantastic.
where
places
Vancouver, where my cousins live, is beautiful.
when
times
2010, when I finished high school, was an important year for me.
whose
possession
Anna, whose car broke down, arrived late.
📝 Important:
Always add a comma before and after the clause (unless it ends the sentence).
Don’t use “that” in non-defining clauses.
3. Comma Rules
Put a comma before and after the non-defining relative clause (unless it’s at the end of the sentence; then you only need one comma).
4. Key Points for Low-Level Learners
You can remove the extra information and the sentence still makes sense.
The verb form inside the clause follows normal grammar rules.
Do not use these clauses to identify someone/something. (Those are defining clauses.)
Examples:
My brother, who lives in Mexico, is visiting next month. (extra info: he lives in Mexico)
The Eiffel Tower, which is in Paris, is very popular. (extra info: its location)
September, when the weather is mild, is my favorite month. (extra info: weather in September)
Chichén Itzá, where millions of tourists go each year, is amazing. (extra info: visitors)
🧠 Compare: Defining vs. Non-Defining
Type
Purpose
Example
Commas?
Use “that”?
Defining
Necessary information
The man who works here is kind. The man that works here is kind.
We use modal verbs like must, have to, need to, and their negatives to talk about things that are necessary or not necessary. For example, rules, duties, or responsibilities. We can also use them to talk about permission in the present or past.
🔹 1. Obligation in the Present
We use must, have to, and need to when something is necessary or important to do.
Structure
Example
Meaning
must + base verb
I must finish this project today.
Strong personal obligation
have to + base verb
I have to work on Saturday.
External rule or schedule
need to + base verb
You need to wear a helmet.
It’s necessary or required
🧠 Tip:
must = personal obligation (you feel it)
have to = external obligation (someone else decides it)
I must study more. (I want to) I have to study more. (My teacher said so)
🔹 2. NO Necessity in the Present
We use don’t have to or don’t need to when something is not necessary.
Structure
Example
Meaning
don’t have to + base verb
You don’t have to come if you’re busy.
It’s optional
don’t need to + base verb
She doesn’t need to wear a uniform.
It’s not required
🧠 Note: They mean the same, but don’t have to is more common in everyday English.
🔹 3. Prohibition (Something Is Not Allowed)
We use mustn’t (must not) to talk about rules or strong advice — when something is not allowed.
Structure
Example
Meaning
mustn’t + base verb
You mustn’t park here.
It’s forbidden
be not allowed to + base form
You are not allowed to park here.
No permission
🧠 Tip: ❌ Don’t confuse mustn’t (not allowed) with don’t have to (not necessary).
You mustn’t smoke here. → It’s against the rules. You don’t have to smoke. → It’s your choice.
🔹 4. Obligation and Necessity in the Past
We can’t use must for the past. Instead, we use had to or needed to.
Structure
Example
Meaning
had to + base verb
I had to finish my homework last night.
It was necessary in the past
needed to + base verb
We needed to buy tickets early.
It was necessary
For the negative, we use didn’t have to or didn’t need to (something was not necessary).
We didn’t have to go to school yesterday. She didn’t need to call — I was already there.
🔹 5. Permission (Present and Past)
We can use be allowed to or could to talk about permission.
Time
Structure
Example
Meaning
Present
am / is / are allowed to/can
Students are allowed to use phones at break. Students can use their phones at break.
We often want to say why we do something, our goal or reason. There are several ways to express purpose in English. Let’s learn and compare them!
1. TO + Base Form
We use to + base verb to show purpose, the reason for an action.
Structure
Example
Meaning
verb + to + base verb
I study hard to pass the exam.
I study for this reason.
verb + to + base verb
She went to the gym to get stronger.
She went there with a goal.
🧠 Tip: Use this for short, direct purposes.
I’m calling to ask a question. He moved to Canada to find a job.
2. IN ORDER TO + Base Form
We use in order to when we want to sound more formal or emphasize the purpose. It means the same as to, but it’s a bit stronger.
Structure
Example
Meaning
verb + in order to + base verb
She left early in order to catch the train.
She left early so she could catch it.
verb + in order not to + base verb
He spoke quietly in order not to wake the baby.
He didn’t want to wake the baby.
🧠 Tip: Use in order to in writing or formal speech.
I’m taking this course in order to improve my skills.
3. SO (THAT) + Subject + Modal + Verb
We use so (that) to explain the purpose of an action, especially when there is a different subject. It’s often followed by can / could / will / would / may / might / should.
Structure
Example
Meaning
so (that) + subject + modal + verb
I’m studying so (that) I can pass my exam.
My goal is to pass.
so (that) + subject + modal + verb
She left early so that she could catch the bus.
She left early to catch it.
🧠 Tip: You can say so that or just so in informal English.
4. FOR + Gerund (-ing)
We use for + -ing to say the general use or purpose of something. It answers “What is this used for?”
Structure
Example
Meaning
for + verb-ing
This brush is for painting.
The brush is used to paint.
for + verb-ing
These shoes are for running.
They’re made for that.
🧠 Tip: Don’t say ❌ for to — just for + -ing.
I use this blog for learning English.
5. FOR + Noun
We also use for + noun to show purpose, especially with things.
Structure
Example
Meaning
for + noun
This medicine is for headaches.
You take it when you have a headache.
for + noun
The bag is for my laptop.
The bag’s purpose is to carry it.
🧠 Tip: Use for + noun when you’re not using a verb.
This room is for meetings. These lessons are for students.
